Form was not a thought. The only objective was completion of an open segmented turning. What I learned during the process, is that it wasn’t worth it! I look at all the beautiful pieces made by true artisans and I halt in awe now knowing how much time goes into each piece… there has got to be a better way!

A 24 segment ring times 5 layers plus a rim and base = 122 pieces. Depending on the glue used each piece sits on the lathe for at least 5 minutes before moving to the next segment. That’s over 10 hours just to glue up! Ridiculous!

To reduce glue up time substantially, my first effort to reduce the time necessary was a hand-cut template for locating the segments. For each layer I would turn the template 6 degrees.

(ugly or what?)

Glue up was 70 minutes for the segments! Consider that this piece was 20 segments times 7 layers with a rim and bottom for a total of 142 pieces. That’s 20 segments more than my first form in about one-tenth the time!!!

Again form was not the objective, proof of concept was. Cutting each segment of the template proved a challenge. This approach worked but accuracy was a problem. To address this (now that I have 9 extra hours) I built a jig to make the templates. If you notice the segment cut out is a removable insert. The insert can now be customized for any possible segment size or quantity.

Accuracy of 30 segment ring made with the jig is much greater but not perfect. I find I still am better off to index the template ring to each level of the glue up.

The concept is proven, now comes the hard work of making something that has nice form!

From the very first day I had a lathe I wanted to try my hand at segmented turnings. These projects can be quite intimidating. For some pieces you must cut hundreds of segments just right before you can ever hope to glue up a piece for turning.

There are several good articles I have found that help you with layout and technique. Kevin’s Woodturnings is one site that really helped me! but I still struggled with the math and figuring out how big to cut each piece.

Here is a tool that should help you, it certainly helped me. I have created an excel spreadsheet that has a separate page for both open and closed segmented turnings. Each page has columns for the nuber of segments in the finished ring. From there the calculations do the rest.

As an example, for an 8 segmented closed circle you would need each division to be 45 degrees. Since you are cutting two pieces to be glued making this 45 degree angle each piece being joined would be cut at 22.5 degree. Simple enough so far….

Next you simply look down the chart to find the radius of the circle you want to make. If it is a 5″ radius, meaning you want a 10″ wide ring, the outer most edge of the segments would need to be cut 4-2/16″ wide.

Cut 8 pie shaped pieces with this dimension and you will be able to glue up a 10″ 8-sided ring.

There you go… have fun, experiment…. but please give me feedback! Let me know if it works, send me a picture of your piece. I’d love to have an example or two to present in my site!

To download the excel file, Click Here  segment-turning-math